Vexes can fly through the world border

Description

Vexes can freely go through the world border.

Expected Result

World border stops vex from going through

Actual Result

Vexes go though the world border freely like through any block.

World border is the thing vexes shouldn't be able to fly through. No other mob/entity can, no entities spawn outside of border and player dies here. But vexes are truly unstoppable